macosx: Fix updating controls bar audio menu items

Certainly biting off more than I chew here but this change appears to fix the issue.

The issue was that visualizations menu checkmarks weren't updating to reflect current selection. E.g when a users selects 'VU Meter', the visualization would appear but the menu would still show 'Disabled' as checked instead of 'VU Meter.'

The issue was also present in the Stereo Audio Mode menu where for example, changing from stereo to mono wouldn't update the selection accordingly.